Thermal technical properties of ecocotton/Ekovatos šiluminės techninės savybės

The purpose of this investigation was to determine thermal technical properties of Ecocotton (or Ecofibre)—thermoinsulating material produced from waste newspaper, boric acid and borax and to evaluate the most optimal areas for application of this material on the basis of this investigation. The density, antiseptic and antipirene quantities of the samples were determined according to [2], thermal conductivity at 25 °C—[4], equilibrium sorbative moisture content—[5], vapour permeability—[6]. The dependencies of dry Ecocotton thermal conductivity on its density and moisture content are given in Figs 1 and 2 as well as after mathematical statistical treatment using the regressive equations (1) and (2). These dependencies are linear. Ecocotton specific heat at 20–25 °C is 1040±100 J/kg · K. The determined equilibrium sorbative moisture content dependency on air relative humidity is given in Table 1 together with literature data about analogous Finnish material Selluvilla-SV. The difference between our and literature data is not significant. The vapour permeability results for Ecocotton are given in Table 2. This value is close to that for mineral wool products. The data about layeral and seasonal distribution of moisture content in Ecocotton and analogous Finnish product Selluvilla-SV used for insulating of attic floors are given in Tables 3, 4 and Fig 3. It was proved on the basis of these results and equilibrium moisture content calculations of building enclosures with insulating layer of Ecocotton, that the calculated equilibrium moisture content of Ecocotton is 9% (to mass). The calculated thermal conductivity and heat capacity coefficients of Ecocotton were calculated according to formulas (3) and (4). Experimental (specific heat C(), kJ/kg ·K: thermal conductivity λ(), W/m·K) and calculated (weight moisture content Ws %; thermal conductivity λ, W/m·K; heat capacity coefficient S, W/m2K; vapour permeability μl, mg/m·h·Pa) thermal technical values for 35, 50 and 75 kg/m3 density Ecocotton are given in Table 5. The most optimal areas for application of Ecocotton are insulation of building enclosures with ventilated air space. First Published Online: 26 Jul 201

Beautoklavio putbetonio šiluminių techninių savybių tyrimai/Investigation into non-autoclaved foam concrete heat engineering properties

The purpose of this investigation was to determine various density foam concrete heat engineering properties. These properties are not included in valid construction standards [1]. Thermal conductivity of samples was determined at 25°C according to [2], specific heat—[3], vapour permeability—[4] and sorption moisture—[5]. Dry foam concrete thermal conductivity (W/m-K) dependency on its density is given in Fig. 1 as well as after mathematical statistical treatment using the regressive equation [1]. Foam concrete thermal conductivity dependency on its humidity statistical analysis results is given in Table 1, here ΔλW s and ΔλW t is the average absolute thermal conductivity increase for 1% materials moisture according to mass and volume, while and δW s δW t is the same increase, but in percentage value. Foam concrete thermal conductivity dependency on moisture is linear. The specific heat value for 245 and 840 kg/m3 density foam concrete is 980±50 and 850±50 J/kg·K respectively. The determined foam concrete sorption moisture is given in Fig. 2 and Table 2. The steep moisture increase at high ambient air humidity is defined by adsorption and the beginning of capillary condensation. This state is not noted in literature curve 2 [7] and evidently due to the short experimental interval. The vapour permeability results for foam concrete are given in Fig. 3 and using the regressive equation (2). Our results are approximately 13% lower than those given for porous concrete [1]. The calculated thermal conductivity was determined using equation (3), assuming that the sorbtion moisture is equal to the relative air humidity (80–85)% (Table 2). Then 250, 500 and 800 kg/m3 density foam concrete λ(ρ0, Wsk) is equal to 0,12, 0,19 and 0,32 W/m·K respectively. The foam concrete heat capacity coefficients S, calculated according to formula (4) for temperature fluctuation period z=24 h and according to damp foam concrete density and specific heat are given in Table 3. Experimental for 260, 500 and 800 kg/m3 density non-autoclaved foam concrete heat engineering values are given in Table 4. For comparison, the denominators (under the line) show the corresponding values for porous concrete given in [1], It is purposive to use in practical calculation specific non-autoclaved foam concrete heat engineering values because these differences are substantial. First Published Online: 26 Jul 201

The equilibrium moisture of building enclosures as function of calculated climatic parameters/Pastatų atitvarinių konstrukcijų nuostoviojo drėgnio priklausomybė nuo skaičiuojamųjų klimato parametrų

The climatic parameters influence the equilibrium moisture of building enclosures and their thermal insulating layers. This investigation seeks to find a quantitative correlation between these influence values. The enclosure equilibrium moisture content W 0 was expressed as the sum of two components: sorption moisture W s and thermal condensation moisture W t (formula 1). The coefficient η was introduced as the maintenance moist state criterion (formula 3), which depends on climatic conditions. It has been used for in-situ investigations of different enclosures (Fig 1) of dwelling houses as well as for damp and wet premises data [4–15]. The results (Fig 2, 3) show the dependence of equilibrium moisture on η. This dependence has been expressed by (4), where W t 0 is W t component due to thermal condensation when η=0. W t 0 is equal to 12,3% (vol) for ceramic and sand-lime, brick masonry as well as for porous concrete, expanded clay aggregate, slag fillings and is equal to 0,028% (vol) for rock wool products in traditional enclosures (Fig 1). The parameter α (7) was introduced for estimating cold season climate influence after mathematical statistical treatment of long-term climatic data [19]. It has been found (Table 1) that a may be adopted to be equal to 0,2 when the equilibrium moisture component due to thermal condensation has been calculated for Lithuanian climatic conditions. The possible equilibrium moisture of various building materials for enclosures has been evaluated by the proposed method and is given in Table 2. The data do not apply to expanded polystyrene, polyurethane foam and cellulose fibre because in-situ investigation data are absent for enclosures with these insulating materials. Table 2 shows that there are several distinctions in given values and corresponding values introduced in abrogated normative documents [25, 26] as well as corresponding corrections Δλw in valid documents [27] stipulated by additional moisture content of materials in enclosures. The correction value Δλw must be defined more precisely when thermal conductivity design values are calculated for enclosures with porous concrete or expanded clay aggregates. Santrauka Išnagrinėtas atitvarinių konstrukcijų nuostoviojo drėgnio ryšys su skaičiuojamaisiais klimatiniais parameirais. Atitvarų nuosiovusis drėgnis W 0 yra išreikštas sorbcinio W s ir termokondensacinio W t įdrėkio suma ir parodyta, kad koeficientas η (3) yra eksploaiacinio drėgminio būvio kriterijus. Atitvarų nuostoviojo drėgnio priklausomybė nuo kriterijaus η veriės pateikta (4). Čia Wt 0—termokondensacinis dėmuo Wt, kai η=0. Bandymų duomenimis, jis lygus 12,3% (tūrio) pilnavidurių keraminių ir silikatinių plytų mūrui, taip pat akytajam betonui, keramzitbetoniui, šlakbetoniui, šlako užpildams ir—0,028% (tūrio) akmens vatos gaminiams tradicinėse atitvarinėse konstrukcijose (1 pav.). Šaltojo periodo klimatui įvertinti taikytas parametras α ir nustatyta, kad skaičiuojant atitvarų nuostoviojo drėgnio termokondensacinį dėmenį Lietuvos klimato sąlygomis α=0,2. Bandymų duomenimis ir atsižvelgiant į galimą klimato parametrų įtaką atitvarų drėgminiam būviui, atliktas galimų atitvarų statybinių medžiagų nuostoviojo drėgnio verčių, į kurias turėtų būti atsižvelgiama nustatant šių medžiagų šilumos laidumo projektines vertes, įvertinimas (2 lentelė). First Published Online: 30 Jul 201

The equilibrium moisture content of low-density thermal insulating materials/Lengvų termoizoliacinių medžiagų nuostovusis drėgnis

Data about water vapour sorption by modern low-density thermal insulating materials are very scarce. The isothermal sorption of water vapour dependent on relative air humidity was investigated for rock and glass wool products in this paper as well as for expanded and extruded polystyrene slabs and cellulose fibre produced in Lithuania, Poland and Estonia. The moisture in these materials is bound by several ways, therefore it is not possibile to express the equilibrium moisture Wp dependency on relative air humidity ϕ by an exact analytical equation [1, 6]. These dependencies were expressed by a two-constant empiric equation (1) for interval ϕ from 0 to 0,97 based on BET equations [1, 7, 8]. The experimental data are given in Figs 1–9, statistical treatment of this data results are given in Tables 1–3. The two fields are typical for all isothermal sorption curves: 0<ϕ<0,8 moisture bound as adsorbate) and 0,8<ϕ<0,97 (capillary bound moisture). The hygroscopicity of investigated glass wool products is higher than for rock wool products and depends on their density. This value is very small for expanded polystyrene and is considerable for cellulose fibre. \ud Santrauka Literatūrinių duomenų apie vandens garų sorbciją, šiuolaikinėse lengvose termoizoliacinėse medžiagose yra nedaug. Straipsnyje ištirtos akmens ir stiklo vatos gaminių, polistireninio putplasčio plokščių ir ekovatos sorbcijos izotermos priklausomybė nuo aplinkos oro santykinio drėgnio ϕ. Kadangi drėgmė šiose medžiagose sujungta keliais būdais, tiksli analizinė šios priklausomybės išraiška yra praktiškai neįmanoma [1, 6]. Todėl, remiantis BET lygtimis [1], ši priklausomybė ϕ intervalu nuo 0 iki 0,97 buvo išreikšta dvikonstante empirine lygtimi (1) [1, 7, 8]. Eksperimentiniai duomenys pateikti 1–9 pav., jų statistinio apdorojimo rezultatai—1–3 lentelėse. Visoms sorbcijos izotermoms charakteringos dvi zonos: 0<ϕ<0,8 (absorbcinis drėgnis) ir 0,8<ϕ<0,97 (kapiliarinis drėgnis). Tyrinėtų stiklo vatos gaminių higroskopiškumas yra didesnis negu akmens vatos gaminių ir priklauso nuo gaminių tankio. Mažiausiai drėgmę iš aplinkos sorbuoja polistireninis putplastis, labiausiai—ekovata

Performance of loose-fill cellulose insulation

Loose fill cellulose thermal insulation known as ecofiber, is a recycled product made from recovered newsprint and other paper feedstocks. The product consists ofsmall tufts ofpaper, dry mixed with powdered chemical additives which improve the fire properties of the product and prevent mould growth. Loose fill cellulose insulation is used in new and renovating buildings. To warrant appropriate thennal-technical conditions and lifetime of this material it needs to take notice to the moist state of enclosures. When moisture content is known in building enclosures, loss factor of thermal conductivity due to materials dampen and select applicable thickness of thermal insulating material can be exactly estimated. The research results of moisture content of loose fill cellulose insulation in exploitation buildings are presented. Moisture content ofcellulosic insulation is determined in one- and two floor buildings with masonry walls made oftwo layers of briks and with different thickness of insulating material layer. Also the influence of moisture content on the thermal conductivity is determined

Stability of strength and deformation characteristics of expanded polystyrene (EPS) within the time of long-term investigation of creep strain under permanent compressive loading

The results of investigation of strength (σ10 %, σcr) and deformability (E) characteristics of expanded polystyrene specimens are presented. The results are based on the short-term compression in the organization of long-term creep study. For the experiments identical specimens stored 5 years at ambient temperature (23 ±2) °C and relative humidity (50 ±5) % as well specimens after removal long-term loading were used. There were established, that difference between experimental values of stress and initial modulus of tested expanded polystyrene specimens with confidence probability P = 90 % (on-sided test) is negligible (random)

Akmens vatos gaminių tarplaboratorinių palyginamųjų bandymų rezultatų analizė

The data obtained in interlaboratory comparison testing programme EA ILC MT2 devoted for testing compression behaviour of mineral wool slabs is discussed in this article. Fifteen laboratories from 11 European countries took part in this PT programme. The satisfactory fulfilling of tests by all laboratories excluding two was confirmed by statistical evaluation of test results. It is revealed the main causes of the test results scattering as well as the expedience to reconsider the Standard, which specifies the procedures for determining compression behaviour of thermal insulating materials.Lietuviška santrauka. Šiame darbe pateikiama akmens vatos gaminių tarplaboratorinių palyginamųjų bandymų, vykdytų ES šalyse 2004 m. (programa EA ILC MT2), rezultatų analizė. Pagrindinis palyginamųjų bandymų tikslas – nustatyti laboratorinių bandymų rezultatų patikimumą. Palyginamųjų bandymų metu buvo nustatomas akmens vatos gaminių gniuždymo įtempis, esant 10 % gaminio deformacijai, ir gniuždymo tamprumo modulis. Papildomai laboratorijos buvo prašomos nustatyti akmens vatos gaminių gniuždymo įtempio, esant 10 % gaminio deformacijai, ir gniuždymo tamprumo modulio matavimo išplėstines neapibrėžtis, bandinių tankį ir organinių medžiagų kiekį bandiniuose. Tiek pluoštinius neorganinius, tiek išputintų polimerų termoizoliacinius gaminius keblu panaudoti Pt bandymams dėl didelių jų homogeniškumo svyravimų. Todėl pastarieji du bandymai buvo naudoti ir bandinių homogeniškumui įvertinti. Laboratorijoje iš plokščių buvo pagaminti 1344 bandiniai. Atlikus išankstinius homogeniškumo bandymus, pagal tankį bei bendrą fizinę jų būklę iš šio masyvo buvo atrinktas tik 161 bandinys tolesniems homogeniškumo bandymams (pagal tankį, organinių medžiagų kiekį, gniuždymo įtempį esant 10% deformacijai σ10% ir gniuždymo tamprumo modulį E) ir paruošti bandinių komplektai programoje dalyvaujančioms laboratorijoms

Assessment of strength under compression of expanded polystyrene (EPS) slabs

The data obtained in testing expanded polystyrene (EPS) slabs subjected to short-term compression are discussed. The results demonstrated that the compressive strength of the slabs should be determined according to critical stress taking into account the type of deformations shown in the stress-strain diagram. The regression equations are provided for calculating the compressive stresses at 10% relative deformation and for critical stress of EPS slabs with the density ranging from 12 to 44 kg/m3

The analysis of interlaboratory testing results of rock wool products mater

The data obtained in interlaboratory comparison testing programme EA ILC MT2 devoted for testing compression behaviour of mineral wool slabs is discussed in this article. Fifteen laboratories from 11 European countries took part in this PT programme. The satisfactory fulfilling of tests by all laboratories excluding two was confirmed by statistical evaluation of test results. It is revealed the main causes of the test results scattering as well as the expedience to reconsider the Standard, which specifies the procedures for determining compression behaviour of thermal insulating materials